COMPARISON OF BLOOD SMEAR MICROSCOPY TO A RAPID DIAGNOSTIC TEST FOR IN-VITRO TESTING FOR P. FALCIPARUM MALARIA IN KENYAN SCHOOL CHILDREN

Abstract

Objective: To compare the diagnostic performance of microscopy using Giemsastained

thick and thin blood smears to a rapid malaria dipstick test (RDT) in

detecting P. falciparum malaria in Kenyan school children.

Design: Children enrolled in a feeding intervention trial were tested for malaria using

microscopy and RDT at baseline, one, and two years. Ongoing morbidity data on

study children was collected through interviews with caretakers regarding signs and

symptoms and physical inspection.

Setting: Rural Embu district, Kenya. The area is considered endemic for malaria, with

four rainy seasons/year. Chloroquine resistance was estimated in 80% of patients.

Children had a spleen rate of 45%.

Subjects: A sample of 515 rural Kenyan primary school children, aged 7-11 years, who

were enrolled in a feeding intervention trial from 1998-2001.

Main outcome measures: Percent positive and negative P. falciparum malaria status,

sensitivity, specifi city, and positive and negative predictive values of RDT.

Results and conclusion: For both years, the RDT yielded positive results of 30% in

children compared to microscopy (17%). With microscopy as the “gold standard,”

RDT yielded a sensitivity of 81.3% in 1998 and 79.3% in 2000. Specifi city was 81.6%

in 1998 and 78.3% in 2000. Positive predictive value was 47.3% in 1998 and 42.6%

in 2000, and negative predictive value was 95.6% in 1998 and 94.9% in 2000. Rapid

diagnostic testing is a valuable tool for diagnosis and can shorten the interval for

starting treatment, particularly where microscopy may not be feasible due to resource

and distance limitations.